Laser angioplasty catheter and a method for use thereof

ABSTRACT

The disclosure relates to a device for use in removing undesired material, e.g., an occlusion or plaque, from a duct or blood vessel within a patient&#39;s body. The device comprises a catheter adapted to be disposed within a duct and having a distal end portion with a tip and a tapered surface extending from the tip to the side of the catheter. The catheter has a lumen extending through the length thereof. The intersection of the lumen and the tapered surface forming an elongated opening. Pulsed laser energy is applied by an optical fiber extending through the lumen to the elongated openings and thereby the undesired material. An inflatable bladder is provided for positioning the distal end portion of the catheter adjacent the inner surface of the duct to position the elongated opening adjacent the undesired material to be removed. A filament extending through the catheter and connected to the distal end portion can be rotated at the proximal end of the catheter to rotatably position the distal portion thereof.

BACKGROUND OF THE INVENTION

This application is commonly owned with a related pending U.S. PatentApplication, Ser. No. PCT/US 86/02617, filed Dec. 2, 1986, in the nameof Michael E. Leckrone and entitled "ANGIOPLASTY CATHETER AND METHOD OFUSE THEREOF".

1. Field of the Invention

The invention relates to laser angioplasty catheters which are adaptedto be inserted into ducts within the body of a patient such as bloodvessels including arteries and veins. The catheters of t he inventionare adapted to penetrate and disintegrate blockages, obstructions,occlusions, etc., or the like within the ducts in which the cathetersare inserted. Thus, the catheters of the invention enable laser energytransmitted by an optical fiber or a bundle of optical fibers to bereleased from the distal end of the catheter to disintegrate or vaporizeobstructions within blood vessels such as plaque in coronary, femoral,and other arteries. In use of an embodiment of the laser angioplastycatheters, the distal end of the catheter is positioned adjacent to theobstruction such as an occlusion or arteriosclerotic plaque which is tobe removed from the duct. Due to the intense and concentrated energylevel of the laser energy, such as pulsed laser energy, the laserangioplasty catheter of the invention must be adapted to prevent thelaser energy from intersecting the internal wall of the duct at an angleor to a degree which could result in the possibility of damaging theduct. In addition, fluids within the duct such as blood within a bloodvessel must be prevented from interfering with the transmission andrelease of the laser energy at the distal end of the catheter. It isalso necessary to have control of the rotational position of the distalend of the catheter with respect to the duct in order that the cathetermay operate upon an obstruction within a duct regardless of itscircumferential position of the obstruction within the duct.

2. Description of the Prior Art

It is known in the prior art to provide a laser angioplasty catheterhaving a flexible shaft adapted to be inserted into a duct such as ablood vessel with a single or solid optical fiber or a bundle of opticalfibers extending through the shaft to adjacent the distal end thereof.Laser energy such as pulsed laser energy is delivered to the proximalend of the optical fiber bundle and is emitted from the distal endthereof. When the laser energy intersects a blockage within the bloodvessel, the laser energy disintegrates or vaporizes the blockage. By theapplication of suction to a lumen extending through the shaft, debrisresulting from the disintegration or vaporization of the blockage can bewithdrawn from the blood vessel

U.S Pat. No. 4,627,436, issued Dec. 9, 1986, discloses a laserangioplasty catheter in which laser energy is delivered to a cavity orjaw formed by spaced abutments at the outer portion of the catheteradjacent to the distal end thereof. An inflatable balloon disposedopposite the abutments can be controllably inflated to urge theabutments toward the inner surface of the duct and thereby receive theblockage with the jaw between the abutments. Laser energy is emitted bythe distal end portion of an optical fiber or fibers into the jaw inorder to vaporize the blockage. The abutments adjacent to the distal endof the catheter prevent the laser energy from being propagateddownstream of the distal end of the catheter and thereby prevent thelaser energy from contacting the inner surface of the duct. A passageextending through the length of the catheter is adapted to apply suctionto the jaw disposed between the abutments in order to remove debristherefrom. By rotating the catheter from the proximal end thereof, thedistal end portion of the catheter can be rotated in order to positionthe abutments and the jaw therebetween within the circumference of theinner surface of the duct.

U.S. Pat. No. 4,685,458, issued Aug. 11, 1987, which is a division ofU.S. Pat. No. 4,627,436, discloses a catheter similar to that of the4,627,436 patent, but with an elongated element such as a cutting bladeor a hot-wire extending between the abutments and adjacent to the jawtherebetween. The blade or hot-wire is adapted to cut or sever ablockage from the inner surface of the duct rather than to vaporize theobstruction by the application of laser energy.

U.S. Pat. No. 4,207,874, issued June 17, 1980, is another example of alaser angioplasty catheter. In this catheter, laser energy disintegratesor vaporizes an obstruction and suction is applied to a passageextending through the length of the catheter to withdraw debris producedby the application of the laser energy.

U.S. Pat. No. 4,573,470, issued Mar. 4, 1986, and U.S. Pat. No.4,582,181, issued April 15, 1986, each disclose a steerable balloondilation catheter in which the distal end of the tubular member of thecatheter is bonded to the distal end of a core wire.

SUMMARY OF THE INVENTION

The invention of a laser angioplasty catheter device for disintegratingor vaporizing undesired material from a duct within the body of apatient comprises a catheter adapted to be disposed within the duct andhaving a snout-shaped distal end portion with a tip at one side thereofand a tapered surface extending from the tip toward the opposite sidethereof. Means are provided adjacent to the distal end of the catheterfor emitting laser energy from an opening in the tapered surfaceobstruction in the duct.

In another embodiment of the invention, means are provided forirrigating the distal end portion of the catheter adjacent to theobstruction being vaporized.

In still another embodiment of the invention, means are provided forremoving debris of the obstruction being vaporized from adjacent thedistal end portion of the catheter.

In an additional embodiment of the invention, the catheter is providedwith a core wire extending through an internal passage within thecatheter to adjacent the distal end portion thereof. At the distal endportion of the catheter, the core wire is secured to the catheter. Withthis arrangement, rotation of the proximal end of the core wire enablesthe distal end of the catheter to be rotated to position thesnout-shaped distal end of the catheter circumferentially adjacent tothe obstruction in the duct of the body of the patient.

In still a further embodiment of the invention, the optical fiber orfibers of the catheter device are extended through a lumen within thecatheter adjacent the distal end portion of the catheter. The distal endof the lumen is provided with an orifice or nozzle which enables thevelocity of a flow of an irrigating fluid delivered by the lumen to becontrolled as it passes out of the orifice.

Therefore it is an object of the invention to provide a laserangioplasty catheter having a snout-shaped distal end portion with atapered surface extending from the tip of the snout-shaped end portionfor emitting pulsed laser energy from an opening in the tapered surface.

It is another object of the invention to provide a laser angioplastycatheter having a lumen for both delivering irrigating fluid to adjacentthe distal end portion of the catheter and receiving the length ofoptical fiber therein.

It is an additional object of the invention to provide a laserangioplasty catheter in which there is provided a core wire extendingthrough a lumen in the catheter and secured to the distal end portionthereof for rotation of the distal end portion in response to rotationof the proximal end portion of the core wire.

It is a further object of the invention to provide a laser angioplastycatheter in which the distal end portion of a lumen for deliveringirrigation liquid is provided with means for controlling the flowdynamics of the liquid to prevent contact of blood or debris with thedistal end portion of the optical fiber or fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of the laser angioplastycatheter of the invention showing the snout-shaped distal end portionthereof and connections to the proximal end portion thereof;

FIG. 2 is a fragmentary plan view of an embodiment of the catheter ofthe invention having a snout-shaped distal end portion;

FIG. 3 is a fragmentary elevation view of the catheter of FIG. 2;

FIG. 4 is a fragmentary vertical section taken along line 4--4 in FIG. 2and showing the optical fibers for directing laser energy through anopening in the snout-shaped distal end portion of the catheter and thearch support for supporting the shaft of the catheter;

FIG. 5 is vertical section taken along line 5--5 in FIG. 4 and showing apassage therein for irrigating fluid and the optical fibers and a lumentherein for aspiration;

FIG. 6 is a vertical section view showing another embodiment of thecatheter device with a guide wire mounted adjacent to the tip of thesnout-shaped distal end portion;

FIG. 7A is a fragmentary plan view showing an arch support for thedistal end of the catheter with the end tab thereof in an intermediateposition;

FIG. 7B is a fragmentary plan view showing the arch support for thedistal end of the catheter with the end tab thereof in its finalposition;

FIG. 8 is a fragmentary perspective view of the exterior of the orificeat the distal end of the arch support;

FIG. 9 is a fragmentary perspective view of the orifice at the distalend of the arch support;

FIG. 10 is a fragmentary vertical section showing an orifice fordirecting irrigation liquid into the elongated opening at the distal endportion of the catheter;

FIG. 11 is a graphical representation of the flow velocity before,through and beyond the orifice of FIG. 10;

FIG. 12 is a graphical representation of the static pressure related tothe velocities shown in FIG. 11;

FIG. 13 is a fragmentary vertical section showing a guidewire extendingthrough the catheter;

FIG. 14 is a fragmentary vertical section showing the aspiration lumenof the catheter;

FIG. 15 is a fragmentary view of the catheter showing an occlusionballoon and a positioning balloon.

FIG. 16 is a fragmentary perspective view showing the snout-shapeddistal end portion adjacent undesired material in a duct;

FIG. 17 is a fragmentary vertical section showing an embodiment of arotatable connection of the optical fiber of the catheter device to asource of pulsed laser energy; and

FIG. 18 is a fragmentary vertical section of another embodiment of arotatable connection of the optical fiber to a source of pulsed laserenergy.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIGS. 1, 2, 3, and 4, the laser angioplasty catheter 30 ofthe invention is adapted to be disposed within a duct in the body of apatient such as a blood vessel or an artery. The catheter shaft 32 has asnout-shaped end portion 33 which terminates in tip 33a. Snout-shapedend portion 33 comprises cylindrical surface 33b at one side and taperedor sloping surface 33c at the opposite side. Thus, the snout-shaped endportion enables the end portion to contact the wall of the blood vesseland then to be deflected toward the center of the interior of the bloodvessel. Within the catheter shaft 32 there is disposed irrigation lumen35 which extends to elongated opening 34 in communication withelliptically-shaped window 33d in tapered surface 33c. As shown in FIG.1, irrigation liquid can be delivered to connector 37 and then throughline 37a to junction 38. By means of coupling 40, the passage of line 39is connected to irrigation lumen 35 and in this way, a flow ofirrigation liquid such as saline can be delivered by irrigation lumen 35to opening 34 and thereby to window 33d.

A fiber optic device such as single or solid optical fiber or a bundleof optical fibers, hereinafter collectively referred to as "opticalfiber", e.g., optical fiber 41 extends from proximal end 32a (FIG. 1) ofthe catheter shaft 32 to the distal end 36a of arch support 36 (FIG. 6).Laser source 42 (FIG. 1) by means of coupling 43 is connected to opticalfiber 44 which leads to rotary connector 45 which enables the opticalfiber 46 to rotate freely with respect to the laser source. Opticalfiber 46 extends from rotary connector 45 to junction 38. Beyond thejunction 38, the optical fiber 46a extends through line 39 which isadapted to carry irrigation fluid from a supply (not shown) to whichcoupling 37 and line 37a are connected. Line 39 is connected to coupling40. Within the coupling 40, optical fiber 41 enter passage 35 whichextends to opening 34.

Aspiration lumen 48 which is shown by dash lines in FIGS. 2 and 3 and inFIG. 5 extends from proximal end portion 32a of the catheter shaft toadjacent elongated opening 34 where the aspiration passage is connectedto aspiration notch 48b (FIGS. 2, 3 and 4) which is on the side of thecatheter opposite elongated opening 34. The proximal end of aspirationlumen 48 within coupling 40 is connected to line 49 which in turn iscoupled to knob 50. Knob 50 has a passage therethrough (not shown). Line49 can be connected by the passage in knob 50 to a source 53 of negativepressure or suction (not shown). It therefore can be seen that upon theapplication of negative pressure to line 49, negative pressure isapplied to aspiration lumen 48 and thereby to notch 48b. By means ofnotch 48b at opening 34, flow can be induced from the adjacent opening34 and into the aspiration lumen 48. The aspiration lumen is optional.If an obstruction adjacent opening 34 is sufficiently disintegrated orvaporized by the laser pulses from the distal end of optical fiber 41,aspiration may not be required.

As shown in FIGS. 5 and 14, as an option, a core wire 54 can be extendedthrough the aspiration lumen 48 if aspiration is not to be used. Distalend portion 54a of the core wire 54 (FIG. 14) is secured by bonding orlike processes to snout-shaped end portion 33 of the catheter 30. Inthis arrangement core wire 54 extends to the proximal end portion 32a(FIG. 1) of catheter shaft 32, extends through coupling 40, and thenthrough the interior of line 49 which provides negative pressure toaspiration passage 48. Further as shown in FIG. 1, core wire 54 can beextended outwardly from coupling 40 and through line 49 to operatingknob 50. Rotation of knob 50 enables core wire 54 to be rotated. Thecore wire may be coated with materials such as fluorocarbon resinmaterials to reduce friction between the core wire and the aspirationpassage when the core wire is rotated.

Rotation of core wire 54 by knob 50 in either of the directions shown bythe arrows in FIG. 1 causes the core wire 54 to rotate freely withinaspiration passage 48; however, since distal end portion 54a (FIG. 14)of the core wire is bonded or secured to snout-shaped end portion 33 ofthe catheter 32, the end portion 33 of the catheter is rotated inconjunction with rotation of the core wire 54. As a result, thesnout-shaped end portion of catheter 33 can be rotated by the core wire54 without rotating the remainder of shaft 32 of catheter device 30. Thecore wire may have a varying thickness with the greater thickness at theproximal end thereof. This provision minimizes "wind-up" in the corewire when it is rotated, increases flexibility at the distal end of thecore wire, and reduces friction and thereby resistance to rotation ofthe core wire in the catheter.

In place of using core wire 54 to rotate the distal end portion 33 ofthe catheter, optical fiber 41 can be used by connecting the distal end41a of the optical fiber to the distal end portion 33 of the catheterwhile the remainder of the optical fiber is free to rotate in its lumen.Thus upon rotating the proximal end 41b of the optical fiber, the distalend portion of the catheter can be rotated.

As shown in FIGS. 1 and 15, the distal end portion of catheter 30 can,as an option, be provided with occlusion balloon 55 and positioningballoon 56. Lumen 57 (FIGS. 3 and 5) which is in communication by port57a (FIG. 3) with the occlusion balloon 55 as shown in FIGS. 1 and 15extends through the catheter shaft 32, through coupling 40, to line 58,through valve 59 to a source of positive liquid (saline, for example)pressure such as syringe 59a. Thus, upon the introduction of positivepressure to passage 57, the occlusion balloon can be inflated, therebysealing off the blood vessel and preventing the flow of blood about thedistal end of the catheter. The level of blood pressure adjacent thesnout-shaped distal end portion 33 of the catheter could cause a flow ofblood along the catheter but for the blocking of the blood vessel by theocclusion balloon. Of course if the catheter of the invention is appliedto arterial blood vessels 65 where the heart and such vessels have beentemporarily bypassed by a blood pumping apparatus, then the occlusionballoon is unnecessary (FIG. 16).

Optional positioning balloon 56 as shown in FIGS. 1 and 15 is connectedby port 62a (FIG. 3) to passage 62 (FIG. 5) which extends through thecatheter shaft 32 to its proximal end portion 32a. Passage 62 isconnected through coupling 40 to line 63 (FIG. 1) which is connected tovalve 64 and in turn to a source of positive liquid pressure such assyringe 65. Upon directing catheter 30 to a position in whichsnout-shaped end portion 33 is adjacent to an obstruction and followingthe optional rotatable positioning of the distal end portion 33 by meansof core wire 34, liquid pressure can be introduced into passage 62 inorder to inflate positioning balloon 56. Since as shown in FIGS. 1 and15, the positioning balloon 52 is disposed at a side of the snout-shapeddistal end portion 33 of the catheter opposite to elongated opening 34,inflation of the positioning balloon 56 can urge the opening 34 to bemoved toward the inner surface of the blood vessel, thereby bringing theocclusion adjacent to the opening 34 for application of pulsed laserenergy thereto.

Guidewire 66 (FIG. 6) which can be a helix of fine filament materialsuch as wire, as an option, can be mounted upon tip 33a of the catheterfor the purpose of guiding the snout-shaped end portion 33 of thecatheter within the blood vessel. Guiding of the catheter by tip 66 canbe augmented by use of core wire 54 in rotating the snout-shaped distalend 33a of catheter 30 to enable the catheter to advance in a desiredmanner with respect to a blood vessel. Marker 67 (FIGS. 2 and 3) whichcan be formed from radio-opaque material such as platinum foil servesthe function of enabling the location of the distal end of catheter 30to be viewed by scanning means such as X-ray, fluoroscope, CAT scan,etc. In this way, the catheter 30 can be observed and controlled bothwith respect to its longitudinal position within the blood vessel aswell as its rotatable position in placing the snout-shaped end portionadjacent to the obstruction.

As shown in FIG. 16, pulsed laser energy can be propagated from opticalfiber 41 at its distal end portion 41a and through opening 34 and window33d thereof to intersect and impinge upon an obstruction 61. Distal endportion 41a can be formed or contoured to provide a substantiallycollimated beam of pulsed laser energy, a convergent beam, or to anextent a divergent beam.

As shown by a dash line 80 in FIG. 1, catheter 30 can be provided withguidewire 80 which extends freely through a passage in knob 50, throughline 49, and through a lumen extending through tip 33a. By way ofexample, guidewire 80 can be extended through aspiration lumen 48 (FIG.13). In use, the guidewire 80 is threaded through the blood vessel underthe control of a scanning device external to the body of the patientsuch as X-ray, CAT scan, etc. until the distal end portion 80a of theguidewire is disposed in the desired blood vessel and adjacent theobstruction which is to be removed. Thereafter, the proximal end of theguidewire is threaded through a passage (not shown) in tip 33a of thesnout-shaped end portion of catheter 30. The catheter is then advancedalong the guidewire 80 and through the blood vessel with the path oftravel of the tip 33a of the catheter being guided b the location of theguidewire. The guidewire 80 can be disposed, as an option, in aspirationpassage 48 (not shown) connecting passage tip 33a of the catheter toaspiration passage 48.

In FIGS. 4, 7A, 7B, 8 and 9, there is shown arch support 36. As shown inFIG. 4, arch support 36 is disposed within the distal end 35a of lumen35 through which optical fiber 41 extends. As shown in FIGS. 7A, 7B, 8and 9, arch support 36 is a semicylindrically-shaped metal shield whichhas an orifice or nozzle 36b in end wall 36a. The metal arch support isdisposed within distal end portion of the irrigation lumen 35. The endwall portion 36a of the metal arch support which is provided withorifice 36b faces and is in communication with opening 34.

As shown in FIG. 4, the distal end portion 41a of optical fiber 41terminates at a distance 36c from the end wall portion 36a of the metalarch support. As shown in the graph of FIG. 11, the flow velocitydecreases in distance 36c. Further as shown, the velocity increases to amaximum within the orifice 36b. Orifice 36b is disposed in facingrelationship with distal end portion 41a of the optical fiber andadjacent opening 34. The orifice forms a window through which laserenergy is transmitted to opening 34. Optical fiber 41 is supported atits distal end portion adjacent to metal arch support 36 by being bondedor cemented to the inner surface 36c of the arch support.

In use, catheter 30 is positioned within a blood vessel 65 until thesnout-shaped end portion 33 is positioned adjacent to an obstruction orthe like in the blood vessel (FIG. 16). Thereafter, the flow irrigationliquid is controlled by orifice or nozzle 36b in being delivered toopening 34. The pulsed laser energy passing through opening 34disintegrates or vaporizes the obstruction 61 adjacent thereto. Themetal arch support 36 protects the distal end portion of the catheterduring the application of the laser energy to the obstruction. Inaddition the metal arch support 36 prevents collapse of the lumen 35whenever balloon 56 is inflated.

In FIGS. 8, 9 and 10, there is shown the orifice 36b of arch support 36.Optical fiber 41 is disposed in the arch support. During the delivery ofpulsed laser energy by optical fiber 41, irrigation fluid is transmittedthrough lumen 35 and into the distance 36b in advance of orifice 36b(FIGS. 13 and 14).

The curve identified as "Flow Velocity" in FIG. 11, shows the relativevelocity of the irrigation fluid within lumen 35, distance 36c andorifice 36b. It can be seen that upon the fluid flow entering the crosssection of the distance 36c which is substantially larger than the crosssection of passage 35, the flow velocity is reduced. Thereafter, as theflow passes through nozzle 36b, the flow velocity increases and reachesa maximum. This arrangement ensures that blood or the debris from anobstruction being disintegrated adjacent opening 34 cannot enter thenozzle 36b or distance 36c and thereby cannot come into contact with thedistal end 41a of the optical fiber. In this way, the possibility ofblood or debris contacting the distal end 41a of the optical fiber anddamaging or destroying the optical fiber is eliminated.

The curve in FIG. 12 marked "Pressure" shows the relative pressure levelof the irrigating fluid in the distal end portion of lumen 35a, indistance 36c, and in orifice 36b. Further as shown in FIG. 10, theorifice 36b serves as an aperture for the laser energy being transmittedtoward opening 34. Thus, the orifice can act as a stop or diaphragm tolimit the size of the beam of laser energy being delivered to opening34.

FIG. 17 shows a rotational connector 99 for a bundle of optical fibers100 which, by way of example may have a diameter of 1,000 microns. Testexperience has shown that where a single fiber or a bundle of opticalfibers are used, the stiffness of the bundle of optical fibers 100 mayprevent the catheter devices as hereinabove described from being rotatedabout the bundle of optical fibers. The rotational connector enablerotation of the optical fiber bundle and thereby enables the catheter tobe rotated. Another requirement of the rotational connector is that itmust be capable of aligning the optical fibers 100 and a laser beam (notshown) directed from a source of laser energy through cavity 101 towardthe proximal end portion 100a of the optical fibers.

Positioner 102 is adapted to be mounted with recess 03 of the outerhousing 104 of a source of laser energy (not shown). Optical fibers 100are fixedly mounted with respect to ferrule 105. The ferrule includesshaft portion 105a and disc portion 105b. Carrier 106 is threadedlymounted within socket 107. The carrier is mounted within bore 102a ofpositioner 102. The positioner is adapted to be translated in orthogonaldirections in a plane at right angles to the axis of the optical fibers100 as shown in FIG. 17 in order to align the distal end portion 100athereof with the laser beam propagated into cavity 101 by the source oflaser energy. Ferrule 105 is rotatably mounted in carrier 106, therebyenabling the optical fibers to be rotated with respect to the source oflaser energy. To position the optical fibers along their longitudinalaxis with respect to the source of laser energy, disc 105b is maintainedat a predetermined position with respect to cavity 101 by thrustbearings 108 mounted in socket 107 which can comprise ball bearings 108in contact with each of the oppositely disposed outer surfaces of disc105b. The result is that the ferrule 105 is free to rotate and yetcannot be translated with respect to the source of laser energy.

Another embodiment of a rotatable connector is shown in FIG. 18, namelyconnector 109. As in the embodiment of FIG. 17, positioner 110 isadapted to be adjustably mounted within recess 111 of housing 112 of thelaser source (not shown). Bearing 113 is a precision roller or needlebearing having outer race 113a and inner race 113b. Socket 114 ispressed into inner race 113b. Sleeve 115 through which optical fibersocket 114. As a result of this arrangement, precision bearing 113 cancontrol the position of the proximal end 116a of the optical fibers inboth a direction radial to the longitudinal axis of the fibers and inthe direction of the longitudinal axis.

What is claimed is:
 1. A laser angioplasty catheter device comprising acatheter having a distal end portion adapted to be inserted within aduct in the body of a patient and a proximal end portion,the distal endportion comprising a tip disposed at one side of the catheter, thedistal end portion having a tapered surface extending from the tip tothe side of the catheter opposite the one side, the catheter having alumen extending through the length thereof and having a distal endportion intersecting the tapered surface extending from the tip of thecatheter, the intersection of the lumen and the distal end portionforming an elongated opening extending along the length of the taperedsurface, an optical fiber extending within the interior of the lumenfrom the proximal end thereof to adjacent and spaced apart from thedistal end portion of the lumen, the optical fiber being adapted to beconnected to a source of laser energy, an elongated annular elementdisposed adjacent the distal end of the lumen and the distal end of theoptical fiber, the annular element having an opening therein fortransmitting laser energy from the optical fiber toward the elongatedopening in the tapered surface to deliver said laser energy through theelongated opening into the duct, and further comprising a cylindricalshield attached to the annular element and extending away from thedistal end of the lumen with the longitudinal axis of the cylindricalshield being substantially parallel to the longitudinal axis of thelumen, the shield being formed of material for absorbing laser energywhich does not pass through the opening in the annular element toprotect the interior surface of the distal end portion of the lumen. 2.A catheter device in accordance with claim 1 in which the cylindricalshield is formed of metal material.
 3. A catheter device in accordancewith claim 1 in which the cylindrical shield is substantiallysemicircular in cross-section.
 4. A laser angioplasty catheter devicecomprising a catheter having a distal end portion adapted to be insertedwithin a duct in the body of a patient and a proximal end portion,thedistal end portion comprising a tip disposed at one side of thecatheter, the distal end portion having a tapered surface extending fromthe tip to the side of the catheter opposite the one side, the catheterhaving a lumen extending through the length thereof and having a distalend portion intersecting the tapered surface extending from the tip ofthe catheter, the intersection of the lumen and the distal end portionforming an elongated opening extending along the length of the taperedsurface, an optical fiber extending within the interior of the lumenfrom the proximal end thereof to adjacent and spaced apart from thedistal end portion of the lumen, the optical fiber being adapted to beconnected to a source of laser energy to deliver laser energy throughthe elongated opening into the duct, and further comprising anadditional lumen extending throughout the length of the catheter, and afilament extending along the length of the additional lumen to adjacentthe distal end of the catheter and movable with respect to the lumen,the filament being connected to the distal end portion of the catheter,the distal end portion of the catheter being adapted to be rotated inresponse to rotation of the filament, whereby the distal end portion ofthe catheter is adapted to be positioned and rotated by the filamentwithin the duct, and in which the filament has a varying thicknessthroughout its length with the maximum thickness thereof being adjacentthe proximal end portion of the catheter and the minimum thicknessthereof being connected to the distal end portion of the catheter.
 5. Alaser angioplasty catheter device comprising a catheter having a distalend portion adapted to be inserted within a duct in the body of apatient and a proximal end portion,the distal end portion comprising atip disposed at one side of the catheter, the distal end portion havinga tapered surface extending from the tip to the side of the catheteropposite the one side, the catheter having a lumen extending through thelength thereof and having a distal end portion intersecting the taperedsurface extending from the tip of the catheter, the intersection of thelumen and the distal end portion forming an elongated opening extendingalong the length of the tapered surface, an optical fiber extendingwithin the interior of the lumen from the proximal end thereof toadjacent and spaced apart from the distal end portion of the lumen todeliver laser energy through the elongated opening into the duct, anadditional lumen extending throughout the length thereof, and a filamentextending along the length of the additional lumen to adjacent thedistal end of the catheter and movable with respect to the lumen, thefilament being connected to the distal end portion of the catheter, thedistal end portion of the catheter being adapted to be rotated inresponse to rotation of the filament, the filament having a varyingthickness throughout its length with the maximum thickness thereof beingadjacent the proximal end portion of the catheter and the minimumthickness thereof being connected with the distal end portion of thecatheter, whereby the distal end portion of the catheter is adapted tobe positioned and rotated by the filament within the duct.
 6. A catheterdevice in accordance with claim 5 in which the filament contains anouter surface conditioned to reduce friction between the filament andthe lumen in which it is disposed.
 7. A catheter device in accordancewith claim 5 in which the outer surface of the filament conditioned toreduce friction comprises a coating of a low surface friction resinmaterial.
 8. A catheter device in accordance with claim 7 in which thelow surface friction resin material comprises a fluorocarbon resinmaterial.
 9. A catheter device in accordance with claim 5 in which thelumen through which the length of the filament extends is an aspirationlumen.
 10. A laser angioplasty catheter device comprising a catheterhaving a distal end portion adapted to be inserted within a duct in thebody of a patient and a proximal end portion,the distal end portioncomprising a tip disposed at one side of the catheter, the distal endportion having a tapered surface extending from the tip to the side ofthe catheter opposite the one side, the catheter having a lumenextending through the length thereof and having a distal end portionintersecting the tapered surface extending from the tip of the catheter,the intersection of the lumen and the distal end portion forming anelongated opening extending along the length of the tapered surface, anoptical fiber extending within the interior of the lumen from theproximal end thereof to adjacent the spaced apart from the distal endportion of the lumen, the optical fiber being adapted to be connected toa source of laser energy to deliver laser energy through the elongatedopening into the duct, an irrigation lumen for delivering irrigationliquid to adjacent the elongated opening, and a nozzle having aconverging opening therein that connects the irrigation lumen to theelongated opening to increase the velocity of irrigation liquid passingthrough the nozzle lumen as the irrigation liquid enters adjacent theelongated opening, the opening of the nozzle transmitting the laserenergy from the distal end portion of the optical fiber to the elongatedopening.
 11. A method for removing undesired material from a duct withina patient's body by use of a catheter having a proximal end portion anda distal end portion, said distal end portion adapted to be insertedwithin a duct in the patient's body, the catheter having means disposedadjacent the distal end portion of the catheter for intersecting andreleasing undesired material from the interior of the blood vessel whenthe distal end portion of the catheter is disposed adjacent to theundesired material, an inflatable bladder mounted on the catheteradjacent the distal end portion thereof; the catheter further includingan irrigation lumen extending through the length of the catheter forpassing a flow of irrigation liquid to the distal end portion of thecatheter, an optical fiber extending within the interior of the catheterfrom the proximal end thereof to the distal end of the catheter todeliver pulsed laser energy to the undesired material and; a filamentextending along the length of the catheter to adjacent the distal end ofthe catheter, the catheter being rotatably disposed about the filamentand adapted to be rotated with respect to the filament;the methodcomprising the steps of: delivering the irrigation liquid from thedistal end of the catheter toward the undesired material adjacent thedistal end of the optical fiber; placing the distal end portion of thecatheter adjacent the undesired material; applying laser energy to theundesired material to release the material from blood vessel; androtating and positioning the distal end portion of the catheter withrespect to the undesired material by rotating the filament.
 12. A laserangioplasty catheter device comprising a catheter having a distal endportion adapted to be inserted within a duct in the body of a patientand a proximal end portion,the distal end portion comprising a tipdisposed at one side of the catheter, the distal end portion having atapered surface extending from the tip to the side of the catheteropposite the one side, the catheter having a lumen extending through thelength thereof and having a distal end portion intersecting the taperedsurface extending from the tip of the catheter, the intersection of thelumen and the distal end portion forming an elongated opening extendingalong the length of the tapered surface, an optical fiber extendingwithin the interior of the lumen from the proximal end thereof toadjacent and spaced apart from the distal end portion of the lumen todeliver laser energy through the elongated opening in the duct, anelongated annular element disposed adjacent the distal end of the lumenand the distal end of the optical fiber, the annular element having anopening therein for transmitting laser energy from the optical fibertoward the elongated opening in the tapered surface, and a cylindricalshield attached to the annular element and extending away from thedistal end of the lumen with the longitudinal axis of the cylindricalshield being substantially parallel to the longitudinal axis of thelumen, the shield being formed of material for absorbing laser energywhich does not pass through the opening in the annular element toprotect the interior surface of the distal end portion of the lumen;whereby the laser energy is adapted to cause excision of undesiredmaterial within the duct when the distal end portion of the catheter isdisposed adjacent to the undesired material and the optical fiber isconnected to a source of laser energy.
 13. A laser angioplasty catheterdevice comprising a catheter having a distal end portion adapted to beinserted within a duct in the body of a patient and a proximal endportion,the distal end portion comprising a tip disposed at one side ofthe catheter, the distal end portion having a tapered surface extendingfrom the tip to the side of the catheter opposite the one side, thecatheter having a lumen extending through the length thereof and havinga distal end portion intersecting the tapered surface extending from thetip of the catheter, the intersection of the lumen and the distal endportion forming an elongated opening extending along the length of thetapered surface, an optical fiber extending within the interior of thelumen from the proximal end thereof to adjacent and spaced apart fromthe distal end portion of the lumen to deliver laser energy through theelongated opening into the duct, the catheter including an irrigationlumen for delivering irrigation liquid to adjacent the elongatedopening, and a nozzle having a converging opening therein connecting theirrigation lumen to the elongated opening to increase the velocity ofirrigation liquid passing through the nozzle lumen as the irrigationliquid enters adjacent the elongated opening, the opening of the nozzletransmitting the laser energy from the distal end portion of the opticalfiber to the elongated opening, whereby laser energy is adapted to causeexcision of undesired material within the duct when the distal endportion of the catheter is disposed adjacent to the undesired materialand the optical fiber is connected to a source of laser energy.
 14. Acatheter device in accordance with claim 13 in which the distal endportion of the optical fiber is spaced apart from the nozzle within theirrigation lumen to form a transition passage for the irrigation liquidin advance of its entry into the nozzle.
 15. A laser angioplastycatheter device comprising a catheter having a distal end portionadapted to be inserted within a duct in the body of a patient and aproximal end portion,the distal end portion comprising a tip disposed atone side of the catheter, the distal end portion having a taperedsurface extending from the tip to the side of the catheter opposite theone side, the catheter having a lumen extending through the lengththereof and having a distal end potion intersecting the tapered surfaceextending from the tip of the catheter, the intersection of the lumenand the distal end portion forming an elongated opening extending alongthe length of the tapered surface, and an optical fiber extending withinthe interior of the lumen from the proximal end thereof to adjacent andspaced apart from the distal end portion of the lumen to deliver laserenergy through the elongated opening in the duct, the optical fiberbeing movable with respect to the lumen, and means connecting theoptical fiber to the distal end portion of the catheter, the distal endportion of the catheter being adapted to be rotated in response torotation of the proximal end of the optical fiber, whereby the distalend portion of the catheter is adapted to be positioned and rotated bythe optical fiber within the duct to enable the laser energy to causeexcision of undesired material within the duct when the distal endportion of the catheter is disposed adjacent to the undesired materialand the optical fiber is connected to a source of laser energy.